An Adaptive Sliding Mode Observer of Induction Motor in Sensorless Vector Control System

A method of using an adaptive sliding mode observer to estimate induction motor rotor flux is presented in this paper, in order to improve the robustness of parametric variation in sensorless vector control. The observer obtains rotor flux and speed by constructing a mathematical model on the basis of the state equation in static coordinate system. Furthermore, the stability of the observer is guaranteed by the Lyapunov stability theory which is analyzed in this paper. The simulation in MATLAB/SIMULINK shows that the adaptive sliding mode observer is robust against motor parametric variation in sensorless vector control system by changing the resistances of stator winding and rotor winding. Finally the experiment based on DSP28335 platform verifies that the observer can obtain the rotor flux and speed in sensorless control system, and the algorithm has good robustness when load and given speed changes.